The present invention relates to expansion bolts and more particularly to an expandable body of an expansion bolt with improved characteristics.
An exploded perspective view of an unfinished expandable body 10 of a conventional expansion bolt is shown in FIG. 1. Expandable body 10 comprises a metal expansion section 12 including an upper section 122 welded to a nut 11, a middle section 24 having a plurality of parallel longitudinal slats 124 with an elongate slot 121 disposed between any two adjacent slats 124, and a lower section 123 welded to a base 13. Once expandable body 10 is formed, a bolt may insert through base 13, enclosed by middle section 24, nut 11 (to form as an expansion bolt), and a piece of object for threadedly securing the expansion bolt to the piece of object. However, the previous design suffered from several disadvantages. For example, the welding processes of nut 11 and base 13 are time consuming and high in manufacturing cost. Further, the structural strength of such welded nut 11 and/or base 13 is not sufficient, resulting in a shortening of the useful life of expansion bolt.
It is therefore an object of the present invention to provide an expansion bolt including a bolt and an expandable metal body comprising an upper section having a hollow upper circular member including a cut and a connection member coupled to the upper section, and a hollow lower circular member including a cut and a dent with the connection member received therein; a middle section having a plurality of parallel longitudinal slots; and a lower section having a plurality of substantially rectangular members on a lower portion. In operation, a piece of object is fastened between lower portion of the lower section and the middle section by driving the bolt in response to an insertion of the bolt through the body and the piece of object. A variety of configurations of upper section and circular members are provided for enhancing the positioning of the expandable body and guiding of the thread of bolt.
The above and other objects, features and advantages of the present invention will become apparent from the following detailed description taken with the accompanying drawings.